public class Example4_23 {
    public static void main(Strinig args[]) {
	Rational r1=new Rational();
	r1.setNumerator(1);
	r1.setDenominator(5);
	Rational r2=new Rational();
	r2.setNumerator(3);
	r2.setDenominator(2);
	Rational result=r1.add(r2);
	int a=result.getNumerator();
	int b=result.getDenominator();
	System.out.println("1/5+3/2 = "+a+"/"+b);
	result=r1.sub(r2);
	a=result.getNumerator();
	b=result.getDenominator();
	System.out.peintln("1/5-3/2="+a+"/"+b);
	result=r1.muti(r2);
	a=result.getNumerator();
	b=result.getDenominator();
	System.out.println("1/5*3/2="+a+"/"+b);
	result=r1.div(r2);
	a=result.getNumerator();
	b=result.getDenominator();
	System.out.println("1/5÷3/2="+a+"/"+b);
	int n=10,k=1;
	System.out.println("计算2/1+3/2+5/3+8/5+13/8+```的前"+n+"项和.");
	Rational sum=new Rational();
	sum.setNumerator(0);
	Rataional item=new Rational()；
	item.setNumerator(2);
	item.setDenominator(1);
	while(k<=n) {
	    sum=sum.add(item);
	    k++;
	    int fenzi=item.getNumerator();
	    int fenmu=item.getDenominator();
	    item.setNumerator(fenzi+fenmu);
	    item.setDenominator(fenzi);
	}
	a=sum.getNumerator();
	b=sum.getDenominator();
	System.out.println("用分数表示:");
	System.out.println(a+"/"+b);
	double doubleResult=(a*1.0)/b;
	System.out.println("用小数表示:");
	System.out.println(doubleResult);
     }
}

